Prior methods for repairing damaged portions of pipelines include moving a liner tube impregnated with a liquid material capable of curing and hardening to a position within the pipe where the damaged portion is located. The liner tube is installed by pulling, pushing, or everting the liner into the host pipe. Once the liner is positioned within the host pipe, it is pressurized, usually by an inflation bladder, causing the liner to press against the interior wall of the host pipe, and the liner is cured by applying heat, such as steam or hot water. These liners can also be cured at ambient temperatures by a chemical mixture which generates an exothermic reaction. The liner tube forms an interior liner in the pipe for the pipeline being repaired. Such a process is known as cured-in-place pipelining.
Lateral or branch pipes are connected to main pipes. In many cases, the connection of lateral pipes to main sewer pipes is accomplished by forming a hole in the main line with a hammer. The lateral pipe is then simply abutted against the hole, and then the juncture is covered with mortar, dirt, or the like. Damage or leaking can occur at the junction between the lateral pipe and the main pipe, which is generally known as one of the weakest points in a collection sewer system. T-shaped or Y-shaped liner tubes have been utilized to fit within the junction between the lateral and main pipes. Liner tubes form a T-shaped or Y-shaped liner after hardening to the interior of the junction between the pipes. Again, inflation bladders are typically used to pressurize the liners against the interior walls of the host pipes.
The liner tubes are often impregnated with a resinous material, which cures and hardens with the addition of either heat or an independent exothermic reaction. At the main and lateral junction, however, the damaged areas often allow the leakage of water. The junction is located at the lowest spot underground of the lateral pipe. Therefore, it is only natural for the water to flow to the area around the junction of the main and lateral pipe. Water tends to seep through the fractures and joints of the junction, and will interact with the resin impregnated liner, and in turn, the liner may not be able to cure to fully repair the junction.
One approach is to inject an expandable liquid grout through the pipe juncture defects so the fluid grout permeates into the soil surrounding the main and lateral pipes. These expandable grouts are activated faster when in communication with water. The grout expands five times its original volume, sealing all points of leakage. A disadvantage to injecting grout first and then inserting a cured-in-place pipe (CIPP) liner is the time and labor necessary to insert two different pieces of equipment in the main pipe and to robotically position those devices with multiple lateral connections. The result is a much greater cost, as the multiple processes would take more time and potentially more people to repair the different areas of the pipe.
Accordingly, there is a need in the art for an improved lining method and apparatus that overcomes the problems resulting from ground water being allowed to penetrate the junction of the main and lateral pipes during the installation process. There is also a need in the art for an improved means and method for lining the junction of the main and lateral pipes that does not require the use of multiple apparatus or lining procedures.